This edition offers comprehensive coverage of ECMAScript 5 (the language standard) and also the APIs introduced in HTML5. The chapters on functions and classes have been rewritten and updated to match different practices. A chapter covers language extensions and subsets. This book is organized into four sections - Learn the core JavaScript language; Understand the scripting environment provided by web browsers with coverage of client-side JavaScript illustrated by many examples; Get a reference for core JavaScript that documents class, object, constructor, method, function, property, and constant; Consult a separate reference to client-side JavaScript, including legacy web browser APIs, the standard Level 2 DOM API, the XMLHttpRequest object, and the canvas tag.